The Special part of Lend Vitae seems just like a holdover from 3e. I would just make it an encounter power. Word of Vitae is a little bit better, but I would still stick with encounter or daily.

Also, shouldn't the damage from Blood Hex be based off Intelligence, like the rest of the blood knight's abilities? I'm guessing it's a typo...

Overall, just seems like a flavor change, with very little mechanical difference. I don't think it will be difficult for a player to have maximum lifedrinker tokens at all times. If that was your intention, then it all works out. If you want to make players care about lifedrinker tokens, however, make it harder to get them, and make them bestow a benefit when you use one, or just make the healing powers better, or something along those lines.